Research on the Input button function of type File

When uploading some websites, a dialog box of [Select File] will pop up when you click the browse button. Many times we need to only upload image files, so in the pop-up [Select File] dialog box, only files in the relevant image format are displayed, and the remaining format files are filtered and not displayed.

For example, http://www.youku.com/v1.0.0326/v/swf/up.swf

This is Youku's video upload selection, which is achieved through the FLASH method to not display non-video files.

FLASH to this effect is generally as described here

import flash.net.FileReferenceList;

var fileRef:FileReferenceList = new FileReferenceList();

var allTypes:Array = [];

var Browsing type:Object = new Object();

Browse type.description = Browse type (*.mp3);

Browse type.extension = *.mp3;

allTypes.push(brow type);

fileRef.browse(allTypes);

So can the <input type=File> in our web page also implement pop-up window to limit the file type?

The solution now can only be to remind users that the format of uploading files is incorrect through monitoring.

<script>

function check(){

var filepath=path.value

filepath=filepath.substring(filepath.lastIndexOf('.') 1,filepath.length)

if(filepath != 'jpg' && filepath != 'gif')

alert (only upload images in JPG or GIF format)

}

</script>

<input type=file name=path onpropertychange=check()> (Only upload images in JPG or GIF format)

<script>

function ck(obj){if(obj.value.length>0){

var af=jpg,gif,png,zip,rar,txt,htm;

if(eval(with(obj.value)if(!/ af.split(,).join(|) /ig.test(substring(lastIndexOf('.') 1,length)))1;)){alert(Allowed file types:/n af);obj.createTextRange().execCommand('delete')};

}}

</script>

<form>

<input type=file name=path onpropertychange=ck(this)/></form>

However, this effect is obviously not as good as FLASH's user experience. It is necessary to follow this type of FLASH upload.